NanoSail-D, which was folded into a package about the size of a loaf of bread, is one of six experiments carried into orbit in November inside a NASA satellite called FASTSAT. The sail was stowed inside a mechanism called a P-POD (Poly PicoSatellite Orbital Deployer), which uses a jack-in-the-box-like mechanism to fling smaller satellites into space.

P-PODs are ordinarily used to release tiny spacecraft directly from their launch vehicles once in orbit, notes Spaceflight Now. But in a first for NASA, NanoSail-D's was to be used to release it directly from another satellite.

On 6 December, initial indications suggested the manoeuvre was successful. But the spacecraft, which is supposed to emit a radio signal that is detectable from Earth, has remained silent.

"We have not been able to locate or make contact with NanoSail-D," says Kim Newton of NASA's Marshall Space Flight Center in Huntsville, Alabama. The sail was scheduled to unfurl on 9 December, but NASA reports that the deployment of the sail cannot be confirmed, and it is not clear whether the sail was successfully ejected into space.

The FASTSAT team is still working on ways to locate and potentially make contact with the sail, FASTSAT project scientist Joe Casas told New Scientist. But progress may be slow. "At this point it's going to be at least a couple of weeks before we have the full assessment of data," Casas says. NASA hopes to use the sail to demonstrate a relatively inexpensive way to pull space debris out of orbit using the drag of Earth's atmosphere.

The sail is a spare copy of an earlier sail, also called NanoSail-D. The original was lost in 2008 when its launch vehicle - a Falcon 1 rocket built by the California-based firm SpaceX - failed to reach orbit. The cost to assemble both sails was $500,000, Spaceflight Now reports.